To enable high quality playback of digital video sequences on high-performance computers, digital video sequences are often recorded and compressed at the maximum frame rate possible (e.g., 30 frames per second). Desktop personal computers often lack sufficient processing power to maintain such maximum frame rates during playback of digital motion video sequences. The platforms and processors in these computers simply function too slowly to decode and display motion video sequences at rates approaching 30 frames per second. The performance of these lower-end systems is further hindered by the fact that, during playback of a motion video sequence, an accompanying digital audio sequence must often also be decoded.
In order to maintain acceptable audio quality during playback, every audio frame in the compressed sequence must be decompressed and output to a sound system. By contrast, it is possible to omit some video frames during playback and still maintain acceptable video quality. However, if during playback video frames are omitted at irregular intervals, the resulting motion video images often suffer from unpleasing skips which make the video images appear jerky.
It is an object of the present invention to dynamically sense during playback whether a decompression system is irregularly omitting frames. If frames are being omitted in an irregular fashion, then it is a further object of the present invention to gradually lower the video frame rate output by the decompression system such that the resulting video which is displayed is as visually pleasing as possible.
It is a further object of the present invention to provide a system for decompressing digital video sequences which can be used on different decompression platforms having differing levels of processing power. It is a still further object of the present invention to provide a system for decompressing digital video sequences which can be selectively configured in response to the processing power of the decompression platform being used.
Further objects and advantages of the invention will become apparent from the description of the invention which follows.